1. Field of the Invention
The present invention relates to a motion picture camera.
2. Description of the Prior Art
In the field of the conventional small size motion picture camera in which a film cartridge is generally used, in the film cartridge known under the name of super-eight, a reversion preventing mechanism allowing only for the forward shaft of the winding up rotation is provided in order to prevent the film from becoming loose. Therefore, in the case of the motion picture camera using such film cartridges it is generally impossible to apply a photographic techniques in which the rewinding of film is necessary, whereby the noise and the vibration produced by the reversion prevention mechanism become problematic.
In case it is desired to apply a photographic techniques such as for example, overlapping photography in which the film rewinding is essential, the film winding up shaft is brought out of the operation for winding up the film for a while, the film being pushed into the film cartridge without being wound up around the film winding shaft so as to be stored loosely therein. The film stored loosely is then returned to the supply side also so as to be stored loosely in the film cartridge and then the film winding up shaft is brought into the film winding up operation, so as to take motion pictures. However, with such a techniques as mentioned above, the film is often curved or folded when the film is stored loosely in the film cartridge in such a manner that not only a bad influence is given to the film but also the film is often broken. However, quite recently, for example, in DOLS 2,322,331, a film cartridge in which the reversion preventing mechanism is releasable in such a manner that in case of necessity a desired quantity of the film already exposed and wound up on the winding up shaft can be rewound already brought on the market. Further, such film cartridges as present such a mechanism and are able to record not only pictures but also sound easily, have also been brought on the market.
In the case of the motion picture camera in which such a film cartridge is to be loaded, it is so designed that at the center of the film winding up claw part corresponding to the film winding up shaft of the film cartridge in the film cartridge containing chamber a projecting pin member is provided in such a manner that the reversion preventing mechanism is released by the central part of the film winding up shaft of the film cartridge by means of the pin member when the film cartridge is loaded in the motion picture camera. Here, for example, in case a synchronous sound recording photography is carried out by using a film cartridge for synchronous sound recording, the reversion preventig mechanism is released when the film cartridge for synchronous sound recording is loaded in order to eliminate the noise and the vibration produced by the reversion preventing mechanism which is disadvantageous especially for synchronous sound recording photography. However, the release part for the reversion preventing mechanism provided in such a film cartridge is arranged in a very small hole at the central part of the film winding up shaft of the film cartridge so that unless the film cartridge is not loaded in the motion picture camera with high precision, the projecting pin does not engage in the hole of the release part correctly in such a manner that the reversion preventing mechanism is not released. Further, in case the film cartridge is not loaded with high precision, the film in the film cartridge is not brought into the correct synchronous sound recording state in the case of the synchronous sound recording photography.
On the other hand, in case of the motion picture camera in the which a conventional film cartridge incapable of releasing the reversion preventing mechanism is loaded, a motion picture camera construction of the so-called drop-in system is often adopted according to which system the film cartridge is loaded in the film cartridge containing chamber, being the film cartridge slid in from the back of the motion picture camera. The motion picture camera according to this system has many advantages such as the easy loading of the film cartridge, the prevention of misloading, the realization of the compact motion picture camera and so on. Especially, a misexposure is completely prevented in case the cover of the cartridge chamber is opened by mistake while the film cartridge is still loaded in the motion picture camera because the part of the film being out of the film magazine and to be exposed is situated at a position quite contrary to the cover of the film cartridge chamber. However, in the case of the motion picture camera in which a film cartridge of the above mentioned new type is loaded, a fixed projecting pin member for releasing the reversion preventing mechanism is provided in the film cartridge containing chamber in such a manner that it is impossible to load a film cartridge in the motion picture camera of the drop-in system according to which system the film cartridge is loaded in the motion picture camera along a direction perpendicular to the axial direction of the projecting pin member because the front end of the cartridge strikes at the pin member. Further, in the case of the motion picture camera so constructed, that due to the conventional winding up claw member, the projecting pin member is movable along the axial direction and provided with a spring, so as normally to project into the film cartridge containing chamber. The projecting pin member is pushed down by a tapered part arranged at the front end of the film cartridge at the time of loading. If the front end of the film cartridge has passed the projecting pin member, the projecting pin projects into the film cartridge containing chamber before the central part is situated at the correct position in the concave portion of the film cartridge winding up shaft in such a manner that the further loading of the film cartridge becomes impossible.
As explained above, in into case of the conventional construction of the motion picture camera, the loading of such a new film cartridge, as mentioned above, in the motion picture camera is often disturbed while it is difficult to realize a new film cartridge loading method presenting many advantages of the drop-in system. Therefore, the application has been limited only to the motion picture camera presenting an opening so designed that the film cartridge can be loaded in the motion picture camera along the same direction as the axial direction of the projecting pin member of the film winding up claw member.